Queen Silvia, front, and her father, Walther Sommerlath, back row, in 1977 (AP)

Sweden’s royal family has been rocked by a new scandal which has exposed the hidden Nazi past of the Queen’s father, only weeks after its reputation was shattered by lurid disclosures about the king’s secret sex life.

The latest revelations concern Walther Sommerlath, the late father of Sweden’s German-born Queen Silvia. He has been unmasked by an investigative television documentary as a Nazi party member who grew rich during the Second World War running an armaments factory that had been stolen from its Jewish owners.

The disturbing revelations, made by Sweden’s Kalla fakta (Cold facts) TV programme, directly contradict 67-year-old Queen Silvia’s claims earlier this year that her father was not “politically active” and that the factory he ran produced toy trains, hairdryers and parts for civilian gas masks. She also denied he had taken over the factory from its Jewish owners.

However, documents unearthed by Kalla facta in Berlin and South America show that Walther Sommerlath joined the Nazi party in Brazil in 1934 – only a year after Hitler took power.

They showed that he returned to Germany shortly before the Second World War broke out in 1939 and took over a previously Jewish-owned Berlin factory that had been “Aryanised” by the Nazis.

Under Sommerlath’s ownership, the plant produced tank parts, anti-aircraft guns and other items vital to the Nazi war effort.

When Silvia Sommerlath married Sweden’s King Carl Gustav in 1976, Walther Sommerlath denied he had ever been a Nazi party member. A Swedish newspaper first revealed the fact in 2003, but the Queen flatly refused to respond to the disclosure at the time. She spoke for the first time about the subject in July this year, saying that although he joined the Nazi party, her father was neither politically active nor a soldier.